Influencia de la diagénesis en la mineralogía de los materiales terciarios del sector central de la depresión del Ebro (Zaragoza)

Abstract

Four profiles built of sandstones, lutites and marls, dated Upper Oligocene-Lower Miocene, and located at the southern central sector of the Ebro basin have been studied, in order to know the postdepositional changes undergone by the original deposits, and the possible use of the inherited clay minerals as paleogeographic and paleoclimatic indicators for this basin. The mineralogical study concludes that illite is the main clay mineral along randon interstratified I-Sm clay minerals. The SEM study confirms that the main process in the deposil of these materials was the inheritance. The postdepositional processes are limited to early diagenesis represented by the development of interstratified I-Sm minerals in degradative processes and by carbonatic cementation of sandstones, in which the effect oí several stages of dissolution and reprecipitation oí carbonates and crystallization oí sulfates and chlorides can be observed.